SDE - 1

You are given an array/list 'prices' where the elements of the array represent the prices of the stock as they were yesterday and indices of the array represent minutes. Your task is to find and return the maximum profit you can make by buying and selling the stock. You can buy and sell the stock only once.

Note:

You can’t sell without buying first.

For Example:

For the given array [ 2, 100, 150, 120],
The maximum profit can be achieved by buying the stock at minute 0 when its price is Rs. 2 and selling it at minute 2 when its price is Rs. 150.
So, the output will be 148.

You are given a non-negative integer ‘num’ in the form of a string and provided with an integer ‘k’.

You need to find the smallest integer possible by removing exactly ‘k’ digits from ‘num.’

Note :

‘num’ does not have leading zeros except when ‘num’ equals zero.

Example:

Input: ‘num’ = ‘141’ , ‘k’ = 1.

Output: ‘11’

Explanation: By removing only 1 digit from ‘num’, 3 numbers can be formed: 14, 11, and 41. Out of which 11 is the smallest number.

Note :

You don’t have to print anything. It has already been taken care of. Just implement the given function.

You’re given a square matrix 'MAT' of order N. Your task is to find the number of non-empty sub-matrices such that the sum of all the elements inside the submatrix is zero.

NOTE:

1. The matrix may also contain some negative elements.
2. A square matrix is a matrix with the same number of rows and columns.
A matrix obtained by deleting some (possibly zero) of the rows and/or columns from the beginning and/or from the end of a matrix is said to be a sub-matrix of the given matrix.

Example: Given a matrix
 A = 1 2
     3 4

Possible non-empty sub-matrices of A are represented below by bold numbers-